Ultrafine grained strips of CuCr0.6 alloy prepared by CRCS method

Purpose: The aim of this work was to evaluate the ability of a continuous repetitive corrugation and straightening (CRCS) technique in creating ultra fine grained copper-chromium strips as well as to determine their deformability, mechanical properties, deformation behaviour and microstructure evolution. Design/methodology/approach: Tests were performed with the 0.8 mm thick CuCr0.6 strips using original die set construction. The changes of mechanical properties as well as microstructure evolution versus number of deformation cycles were investigated. The microstructure was investigated using optical and electron microscopy (TEM and SEM equipped with EBSD). Findings: The obtained strengthening effects and observed microstructure changes have been discussed basing on the existing theories related to strengthening of ultra fine grained copper based materials. The CRCS process effectively reduced the grain size of a CuCr0.6 alloy strips, demonstrating the CRCS as a promising new method for producing ultra fine grained metallic strips. Research limitations/implications: Research results are limited to the initial material after annealing only. Further investigations should be aimed towards determination of CRCS sequence including deformation-precipitation-ageing influence on strengthening effect. Practical implications: A growing trend to use new copper-based functional materials is observed recently world-wide. Within this group of materials particular attention is drawn to those with ultra fine or nanometric grain size of a copper matrix, which exhibit higher mechanical properties than microcrystalline copper. Originality/value: The paper describes to the mechanical properties of precipitates strengthened ultra fine grained copper - chromium alloy strips obtained by original RCS method and to the microstructure evolution.